To achieve energy saving, speedup, and space saving of image forming apparatuses, there is a need for a toner for electrostatic image development (hereinafter may be referred to simply as a “toner”) that has better low-temperature fixability. One known toner is designed such that a crystalline polyester resin having sharp melting properties is introduced into the toner to lower the glass transition point and melt viscosity of a binder resin.
In such a toner, the balance of affinity between an amorphous resin introduced as a main resin such as an amorphous polyester resin and crystalline materials such as the crystalline polyester resin and a wax is controlled to suppress bleeding of the crystalline materials to the surface of toner particles, and sufficient post-fixing separability must thereby be ensured.
For example, Patent Literature 1 discloses a toner in which dodecenyl succinic acid is used as a constituent amorphous polyester resin. In this toner, the affinity between the amorphous polyester resin and the crystalline materials is improved through a side chain of dodecenyl succinic acid. Patent Literature 2, for example, discloses a toner containing a dispersant composed of a crystalline material.
However, even with these toners, bleeding of the crystalline materials cannot be suppressed sufficiently, and both low-temperature fixability and post-fixing separability are not achieved simultaneously in a satisfactory manner.